EN 61472-2013 en Live working - Minimum approach distances for a c systems in the voltage range 72 5 kV to 800 kV - A method of calculation.pdf

1、BSI Standards PublicationLive working Minimumapproach distances for a.c systems in the voltage range 72,5 kV to 800 kV A method of calculationBS EN 61472:2013Incorporating corrigendum October 2015National forewordThis British Standard is the UK implementation of EN 61472:2013. It is The UK participa

2、tion in its preparation was entrusted to TechnicalCommittee PEL/78, Tools for live working.A list of organizations represented on this committee can be obtained onrequest to its secretary.This publication does not purport to include all the necessary provisions ofa contract. Users are responsible fo

3、r its correct application. The British Standards Institution 201Published by BSI Standards Limited 2016ISBN 978 0 580 92887 1ICS 13.260; 29.240.20; 29.260.99Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of theS

4、tandards Policy and Strategy Committee on 31 July 2013.Amendments/corrigenda issued since publicationDate Text affectedBRITISH STANDARDBS EN 61472:2013identical to IEC 61472:2013, incorporating corrigendum October 2015. It supersedes BS EN 61472:2004, which will be withdrawn on 16 May 2016.The start

5、 and finish of text introduced or altered by corrigendum is indicated in the text by tags. Text altered by IEC corrigendum October 2015 is indicated in the text by .Implementation of IEC corrigendum October 201531 March 20166.EUROPEAN STANDARD EN 61472NORME EUROPENNE EUROPISCHE NORM July 2013 CENELE

6、C European Committee for Electrotechnical Standardization Comit Europen de Normalisation Electrotechnique Europisches Komitee fr Elektrotechnische Normung Management Centre: Avenue Marnix 17, B - 1000 Brussels 2013 CENELEC - All rights of exploitation in any form and by any means reserved worldwide

7、for CENELEC members. Ref. No. EN 61472:2013 E ICS 13.260; 29.240.20; 29.260.99 Supersedes EN 61472:2004 English version Live working - Minimum approach distances for a.c systems in the voltage range 72,5 kV to 800 kV - A method of calculation (IEC 61472:2013) Travaux sous tension - Distances minimal

8、es dapproche pour des rseaux courant alternatif de tension comprise entre 72,5 kV et 800 kV - Une mthode de calcul (CEI 61472:2013) Arbeiten unter Spannung - Mindest-Arbeitsabstnde fr Wechselspannungsnetze im Spannungsbereich von 72,5 kV bis 800 kV - Berechnungsverfahren (IEC 61472:2013) This Europe

9、an Standard was approved by CENELEC on 2013-05-16. CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references

10、concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CENELEC member. This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CENEL

11、EC member into its own language and notified to the CEN-CENELEC Management Centre has the same status as the official versions. CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic, Denmark, Estonia, Finland, Former Yugoslav

12、Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. EN 61472:2013 Foreword The text of document 78/10

13、04/FDIS, future edition 3 of IEC 61472, prepared by IEC/TC 78 “Live working“ was submitted to the IEC-CENELEC parallel vote and approved by CENELEC as EN 61472:2013. The following dates are fixed: latest date by which the document hasto be implemented at national level bypublication of an identical

14、nationalstandard or by endorsement(dop) 2014-02-16 latest date by which the nationalstandards conflicting with thedocument have to be withdrawn(dow) 2016-05-16 This document supersedes EN 61472:2004. This document has been prepared according to the requirements of EN 61477: Live working Minimum requ

15、irements for the utilization of tools, devices and equipment, where applicable. EN 61472:2013 includes the following significant technical changes with respect to EN 61472:2004: clarification of the scope; review of the definitions; clarification of the methodology of determining whether live workin

16、g is permissible and the calculation ofthe minimum approach distances; modification of the basic equation for calculation of the minimum approach distance; introduction of Table 1 for altitude correction factor simplification ka; introduction of criteria in presence of composite insulator and clarif

17、ication on the use of insulator factorki; review of the informative Annex F on the influence of floating conductive objects on the dielectricstrength; review of the informative Annex G on live working near contaminated, damaged or moist insulation.Attention is drawn to the possibility that some of t

18、he elements of this document may be the subject of patent rights. CENELEC and/or CEN shall not be held responsible for identifying any or all such patent rights. Endorsement notice The text of the International Standard IEC 61472:2013 was approved by CENELEC as a European Standard without any modifi

19、cation. In the official version, for Bibliography, the following notes have to be added for the standards indicated: IEC 60060-1:2010 NOTE Harmonised as EN 60060-1:2010 (not modified). IEC 60071-1:2006 NOTE Harmonised as EN 60071-1:2006 (not modified). IEC 60071-2:1996 NOTE Harmonised as EN 60071-2:

20、1997 (not modified). IEC 60743 NOTE Harmonised as EN 60743. IEC 61477:2009 NOTE Harmonised as EN 61477:2009 (not modified). BS EN 61472:2013 2 61472 IEC:2013 CONTENTS 1 Scope . 6 2 Terms, definitions and symbols 6 2.1 Terms and definitions 6 2.2 Symbols used in the normative part of the document . 8

21、 3 Methodology . 9 4 Factors influencing calculations 10 4.1 Statistical overvoltage . 10 4.2 Gap strength . 10 4.3 Calculation of electrical distance DU. 11 4.3.1 General equation . 11 4.3.2 Factors affecting gap strength . 11 5 Evaluation of risks 16 6 Calculation of minimum approach distance DA.

22、17 Annex A (informative) Ergonomic distance . 18 Annex B (informative) Overvoltages . 20 Annex C (informative) Dielectric strength of air 24 Annex D (informative) Gap factor kg26 Annex E (informative) Allowing for atmospheric conditions 28 Annex F (informative) Influence of floating conductive objec

23、ts on the dielectric strength 32 Annex G (informative) Live working near contaminated, damaged or moist insulation 40 Bibliography 45 Figure 1 Illustration of two floating conductive objects of different dimensions and at different distances from the axis of the gap . 13 Figure 2 Typical live workin

24、g tasks . 15 Figure B.1 Ranges of ue2at the open ended line due to closing and reclosing according to the type of network (meshed or antenna) with and without closing resistors and shunt reactors 22 Figure F.1 Influence of the length of the floating conductive objects phase to earth rod-rod configur

25、ation 250 s /2 500 s impulse 35 Figure F.2 Influence of the length of the floating conductive objects phase to phase conductor-conductor configuration 250 s /2 500 s impulse . 36 Figure F.3 Reduction of the dielectric strength as a function of the length D for constant values of Phase to earth rod-r

26、od configuration 37 Figure F.4 Reduction of the dielectric strength as a function of the length P for constant values of Phase to phase conductor-conductor configuration 37 Figure G.1 Strength of composite insulators affected by simulated conductive and semi-conductive defects . 43 Table 1 Average k

27、avalues . 12 Table 2 Floating conductive object factor kf. 14 Table B.1 Classification of overvoltages according to IEC 60071-1 20 BS EN 61472:201361472 IEC:2013 3 Table D.1 Gap factors for some actual phase to earth configurations . 27 Table E.1 Atmospheric factor kafor different reference altitude

28、s and values of U90. 30 Table G.1 Example of maximum number of damaged insulators calculation (gap factor 1,4) . 41 Table G.2 Example of maximum number of damaged insulators calculation (gap factor 1,2) . 42 BS EN 61472:2013 6 61472 IEC:2013 LIVE WORKING MINIMUM APPROACH DISTANCES FOR A.C. SYSTEMS I

29、N THE VOLTAGE RANGE 72,5 kV TO 800 kV A METHOD OF CALCULATION 1 Scope This International Standard describes a method for calculating the minimum approach distances for live working, at maximum voltages between 72,5 kV and 800 kV. This standard addresses system overvoltages and the working air distan

30、ces or tool insulation between parts and/or workers at different electric potentials. The required withstand voltage and minimum approach distances calculated by the method described in this standard are evaluated taking into consideration the following: workers are trained for, and skilled in, work

31、ing in the live working zone; the anticipated overvoltages do not exceed the value selected for the determination of the required minimum approach distance; transient overvoltages are the determining overvoltages; tool insulation has no continuous film of moisture or measurable contamination present

32、 on the surface; no lightning is seen or heard within 10 km of the work site; allowance is made for the effect of conducting components of tools; the effect of altitude, insulators in the gap, etc, on the electric strength is taken into consideration. For conditions other than the above, the evaluat

33、ion of the minimum approach distances may require specific data, derived by other calculation or obtained from additional laboratory investigations on the actual situation. 2 Terms, definitions and symbols For the purpose of this document, the following terms, definitions and symbols apply. 2.1 Term

34、s and definitions 2.1.1 damaged insulator insulator having any type of manufacturing defect or in-service deterioration which affects its insulating performance 2.1.2 electrical distance DUdistance in air required to prevent a disruptive discharge between energized parts or between energized parts a

35、nd earthed parts during live working SOURCE: IEC 60050-651:, 651-21-12 BS EN 61472:201361472 IEC:2013 7 2.1.3 ergonomic distance ergonomic component of distance DEdistance in air added to the electrical distance, to take into account inadvertent movement and errors in judgement of distances while pe

36、rforming work SOURCE: IEC 60050-651:, 651-21-13 2.1.4 fifty per cent disruptive discharge voltage U50peak value of an impulse test voltage having a fifty per cent probability of initiating a disruptive discharge each time the dielectric testing is performed SOURCE: IEC 60050-604:1987, 604-03-43 2.1.

37、5 highest voltage of a system Ushighest value of operating voltage which occurs under normal operating conditions at any time and any point in the system (phase to phase voltage) Note 1 to entry: Transient overvoltages due e.g. to switching operations and abnormal temporary variations of voltage are

38、 not taken into account. SOURCE: IEC 60050-601:1985, 601-01-23, modified A reference to phase to phase voltage has been added. 2.1.6 minimum approach distance minimum working distance DAminimum distance in air to be maintained between any part of the body of a worker, including any object (except to

39、ols appropriate for live working) being handled directly, and any part(s) at different electric potential(s) Note 1 to entry: The minimum approach distance is the sum of the electrical distance appropriate for the maximum nominal voltage and of the selected ergonomic distance. SOURCE: IEC 60050-651:

40、, 651-21-11 2.1.7 minimum residual insulation length DLinsinsulation length required to prevent a disruptive discharge between energized parts and earthed parts measured along the insulator length, taking into account the presence of floating conductive objects and of damaged insulator portions 2.1.

41、8 ninety per cent statistical impulse withstand voltage U90peak value of an impulse test voltage at which insulation exhibits, under specified conditions, a ninety per cent probability of withstand Note 1 to entry: This concept is applicable to self-restoring insulation. SOURCE: IEC 60050-604:1987,

42、604-03-42, modified The definition has been changed to refer specifically to a ninety per cent probability of withstand. BS EN 61472:2013 8 61472 IEC:2013 2.1.9 part any element present in the work location, other than workers, live working tools and system insulation 2.1.10 per unit value u express

43、ion of the per unit value of the amplitude of an overvoltage (or of a voltage) referred to Us2 / 3 Note 1 to entry: This applies to ue2and up2defined in Clause 4. 2.1.11 transient overvoltage short duration overvoltage of few milliseconds or less, oscillatory or non-oscillatory, usually highly dampe

44、d SOURCE: IEC 60050-604:1987, 604-03-13, modified The two notes in the original definition have been deleted. 2.1.12 two per cent statistical overvoltage U2peak value of a transient overvoltage having a 2 per cent statistical probability of being exceeded 2.1.13 work location any site, place or area

45、 where a work activity is to be, is being, or has been carried out SOURCE: IEC 60050-651:, 651-26-03 2.2 Symbols used in the normative part of the document Adlength of damaged insulator or number of damaged units in an insulator of length Ao, not shunted by long arcing horn or grading ring Aolength

46、of undamaged insulator or number of undamaged insulator units not shunted by long arcing horn or grading ring ratio of the total length in the direction of the gap axis of the floating conductive objects (s) to the original air gap length D length of the remaining air gap phase to earth DAminimum ap

47、proach distance DEergonomic distance DUelectrical distance necessary to obtain U90DLinsminimum residual insulation length d1, d2, d3,d4distances between the worker(s) and parts of the installation at different electric potentials (see Figure 2) F sum of all lengths, in the direction of the gap axis,

48、 of all floating conductive objects in the air gap (in metres) BS EN 61472:201361472 IEC:2013 9 Ksstatistical safety factor Ktfactor combining different considerations influencing the strength of the gap kaatmospheric factor kdcoefficient characterizing the average state of the damaged insulators kf

49、floating conductive object factor kggap factor kidamaged insulator factor kicdamaged composite insulator factor kisdamaged insulator strings factor ksstandard statistical deviation factor Lforiginal air gap length P length of the remaining gap phase to phase r distance of a conductive object from the axis of the gap senormalized value of the standard deviation of U50expressed in per cent U2two per cent statisti